مجله سامانه های سطوح آبگیر باران
سال پنجم شماره 2 (پیاپی 15، تابستان 1396)

Integrated Watershed Management requires knowledge and awareness regarding socioeconomic factors affecting planning, implementation and maintenance of watershed management projects. The purpose of this study was to investigate, identify and analyze factors affecting the success of watershed management projects from experts’ points of view. Our study was a quantitative, descriptive-analytical, applied research for which data was collected using surveys. The statistical population consisted of all experts in the Department of Natural Resources of South Khorasan Province (45 individuals) and professors and graduate students in the field of range and watershed management at the University of Birjand (12 individuals). The results showed that from the perspective of the statistical population, " participatory factors", "educational and promotional factors" and "social characteristics of stakeholders" have the greatest impact on the success of watershed management projects. The findings also showed " participation of the residents of a watershed in project implementation", "visits to successful projects by beneficiaries", "compatibility of projects with the needs of stakeholders" and "employment of qualified, skillful experts in the execution of projects" are the most important drivers of the effectiveness and success of watershed management projects.

Iran’s location on Earth’s dry belt, and the consequent low precipitation, temporal and spatial changes in precipitation, have placed immense importance to the planning and management of water resources in the country. Thus, modeling can be viewed as one of the methods to investigate flood potential due to land use change. The aim of this study is to determine sites for water harvesting reservoirs for urban landscape applications in Tehran’s first district using the SWMM model; in order to efficiently use water resources, in addition to mitigating damage caused by runoff accumulation downstream and increased pollution. The SWMM model was used to simulate precipitation-runoff. After running the model, 2 events were used to calibrate the model and one event was employed to evaluate the model to confirm its validity and efficiency. The Nash-Sutcliffe coefficient was used to measure efficiency, producing values greater than 0.5 for all three events which confirmed the accuracy of our model. In the next step, factors influencing the possible site of reservoirs were determined using satellite images and GIS software capabilities, which indicated “proximity of the site of accumulation to site of consumption”, “significant volume of runoff”, “site’s suitability for construction”, and “ownership by the city’s municipality” as primary factors. “Distance from raw water supply network”, “existence of a reservoir”, “history of flooding”, “water supply limitations”, and “future development needs” were determined as secondary factors. The results revealed 23 suitable point for runoff storage reservoirs in Tehran’s first district for landscape applications in such a manner that in precipitation events with return periods of two and five years, 3892 and 4880 m3 of runoff pass through the 23 proposed sites. The results point to the district’s potential for development of water harvesting systems which can reduce pressure on subterranean water resources and address some of the challenges faced in the maintenance and extension of urban landscapes through use of unconventional sources of water.

Groundwater is one of the most important water resources, making it fundamental to human life and economic development in arid and semi-arid regions such as Iran. The mean annual precipitation of Iran is about 240 mm, roughly a third of the global average. Until the 1940s groundwater was extracted by means of the indigenous Qanats system. Currently, the existence of 41000 of Qanats is recorded in Iran. However, in the period of 1971-2013 the number of wells increased from just over 47000 to almost 789000. Today about 196000 deep and 593000 shallow wells have been dug all over the country with a mean discharge of about 0.17×10-3 million cubic meters (MCM) and 0.02×10-3 MCM respectively. Based on our results, the volume of groundwater exploitation (through wells, Qanats and springs) has risen from less than 18 MCM annually in the early 1970s to over 79 MCM in 2005. However, groundwater exploitation has reduced since 2005, and reached about 61 MCM in 2015. The results also show that agriculture is the sector with the highest water demand. Over 90 percent of the extracted ground water resources are consumed in agriculture. Finally, in recent years annual average water table drawdown rate has been about 0.51 m/yr and the total overexploitation of groundwater has been calculated at 5.086 MCM/yr. Of a total 609 areas studied, 347 are prohibited areas.

One of the most important activities that can be evaluated in the management of flood water spreading is recognition of flood water spreading systems operation and artificial recharge of aquifers in relation with other natural factors affecting the recharge of aquifers. The purpose of this paper is evaluating the effect of floodwater spreading projects on flood control and recharge of downstream groundwater aquifer in Fasa Gareh Baygon plain in the unprecedented flood event of Feb. 2017. For the purpose of aforementioned study, variation of floodwater depth in the Bishehzard River during the period of the flood event (13.02.2017 to 18.02.2017) and volume of outflow and inflow were measured. The results showed that the maximum depth of the flood in river was 176 cm with a maximum flow of 330 m3/s. Within the water spreading system, this depth changes into a thin layer of 8 cm on the edge of the spreading channels, which caused not only control of flood velocity but also prevented soil erosion. In order to understand the role of flood water spreading on aquifer recharge, 6 observation wells (piezometers) and 1 well were monitored for 2 months before and 5 months after the floods occur. The results showed that 2 months after the occurrence of flood, water started to affect the aquifer. In this event, about 9924313 cubic meters (between 9281731 and 11423670 cubic meters) of water was penetrated into the aquifer. The drinking water well of the Kowsar station (W1() located at the center of the flood water spreading system,far from the agricultural harvesting area and outside the forest region) shows the highest increase of water level (2.5 m). Sustainable groundwater supply is essential for continuing activity in this area and similar regions. Based on the results of this study and researches carried out in 37 other parts of the country, it is possible to manage the water with a high degree of reliability by implementing flood water spreading systems. Readiness to use rare events happening in these kind of areas is very necessary.

For planning and implementing water-related projects, applying new models and methods is necessary to determine water balance components in basins. Therefore, in this research daily runoff of the Gamasiab basin in the south of Hamadan and Kermanshah provinces was simulated based on cellular network using the spatially semi-distributed SWAT hydrological model in a GIS environment. Digital maps of elevation (DEM), land use, and soil texture and continuous time series of temperature, precipitation, evapotranspiration and discharge were the main model inputs. The model simulates all water balance components in each hydrologic response unit (HRU) and sub-basin using rainfall, temperature and evaporation data. Calibration of model parameters was done for the last 20 years of the studied period (1990-2009) and validation of the model was performed for the first 5 years (1984 to 1989). Based on the results of the simulation, 28% of the area’s total rainfall is discharged from the basin as runoff which nearly matches the data observed at the hydrometric outlet station. Subsequently, to evaluate the model’s performance, simulated values of precipitation, evaporation and discharge were compared with observed data. There was a good agreement between observed and simulated data based on the Nash-Sutcliffe efficiency index (0.6). Hence, it can be concluded that, this model is able to simulate surface and subsurface runoff, deep infiltration and evapotranspiration in the Gamasiab basin.

Providing water to people in arid and semi-arid areas of the world is especially important. Therefore, identification of suitable sites for the construction of rainwater harvesting systems is an important step towards maximizing available water for agriculture and other uses. The purpose of this study is to identify areas susceptible to penetration by rainwater, where rainwater can be collected to restore water resources and enhance vegetation cover, and to be used in different ecosystems of Khosrowabad watershed using hierarchical decision making method based on spatial analysis in a GIS environment. In this research, the factors affecting rainwater penetration and storage in the soil profile of Khosrowabad watershed in the city of Sonqor were identified and entered into the Analytical Hierarchy Process (AHP) process. The selected indices were evaluated using a questionnaire and evaluated by experts’, academics’ and specialists’ opinion by group method during the process of value engineering and were later compared individually and in pairs. Then, their importance coefficients were determined and the paired comparison tables completed. The completed tables were analyzed by the special vector method. In this regard, the weight of seven criteria of vegetation, slope, precipitation, land use, hydrological groups, elevation classes and erosion were calculated using MATLABR2009a software and the required layers were prepared in Arc GIS10.3 environment. Then, using natural breaks in GIS environment, the five levels determined as very appropriate, appropriate, moderate, inappropriate, and unsuitable. From 1855/67 hectares, the total area of ​​the catchment area is 862,600 hectares. The total area of ​​the basin has a suitable and very suitable potential for collecting rainwater and 259.49 hectares of the catchment area with inappropriate and very inappropriate potential for this purpose, reflecting the very high capacity of this basin to store and collect rainwater. The results of this study showed that in addition to the precipitation factor which is one of the main factors, the two factors of gradient and soil characteristics in terms of soil hydrological groups are the more important factors for collecting rainwater compared to the rest of factors and have a more significant impact.

Groundwater and water resource management play key roles in water resource sustainability in arid and semi-arid areas. Forecasting groundwater level is very important for water resource management and planning. In this study, an artificial neural network and a particle swarm algorithm based on artificial neural network models have been used to estimate groundwater level in the Ardebil plain. Water table level data for the 1972 -2011 period was used as our data in this study. Model inputs were water table level of various months. Results of both models were evaluated by root-mean-square error, the correlation coefficient and Nash-Sutcliffe coefficient. Results showed the performance of the particle swarm algorithm based on artificial neural network models to be superior. Root-mean-square error results for the particle swarm algorithm model in spring, summer, autumn and winter were 0.476, 0.507, 0.309, and 0.386 respectively. These results show that the hybrid structure of the network in training leads to increased accuracy. Thus, the particle swarm algorithm based on artificial neural network models can be used to estimate groundwater level in the Ardebil plain with acceptable accuracy.